One of my absolute favorite marvels of the natural world is bioluminescence. The idea that some creatures can generate light from their bodies has always captivated and mystified me. It wasn’t until now, though, that I decided to do some research on it. This unusual yet fascinating phenomena will hopefully interest you as much as it has me.
Most animals that are able to generate light are found in the darkest depths of the ocean. The disphotic, or “twilight,” zone of the ocean’s depths, which is about 660-3300 feet below the surface, is host to such creatures. At this level, very little sunlight is visible. Seawater absorbs red, yellow, and orange sunlight and scatters violet light, so the only color of sunlight you’d see is a dim blue-green. Blue-green light has a short wavelength, so it penetrates the water more easily. Plenty of bioluminescent animals live at this depth, including jellyfish, squid, shrimp, krill, marine worms and fish. The wavelength of their body light nearly matches the sunlight, but in some places, the animals themselves are the main source of light, not the sun.
Of course, animals that can light themselves up above the water as well. Glow worms are yet another source of natural light. They are mainly the larva of various flies and beetles. One perhaps unexpected creator of bioluminescence is a certain fungus that feeds on rotting wood. At night, they glow intensely, a phenomena called foxfire.
The iconic light-up animal, a summertime insect commonly known as the firefly, is well-known for its shining yellow rear end. Some people think that only adult fireflies glow, but even the larvae do. Fireflies will use their light for a few different purposes. For instance, it can be utilized to ward off predators by warning them of bitter-tasting/poisonous chemicals. More often, though, the males will flash a specific pattern in an attempt to attract a female mate.
Fireflies produce light via a chemical reaction consisting of Luciferin (a substrate) combined with Luciferase (an enzyme), ATP (adenosine triphosphate), and oxygen. When these components are added, light is produced. This reaction is very similar to that of photosynthesis in plants, something that was discussed in class. The major difference, of course, is that in bioluminescence, light is produced instead of absorbed.
As you can see, bioluminescence is a fascinating and beautiful process. It has become known as one of nature’s greatest visual marvels.
How is bioluminescence similar to photosynthesis?
What are some other purposes bioluminescence might serve to the animals that can perform it?
How do you think bioluminescence came to be able to be performed by certain animals?